Christoph Kittl

The Role of the Anterolateral Structures and the ACL in Controlling Laxity of the Intact and ACL-Deficient Knee

Background: Anterolateral rotatory instability (ALRI) may result from combined anterior cruciate ligament (ACL) and lateral extra-articular lesions, but the roles of the anterolateral structures remain controversial. Purpose: To determine the contribution of each anterolateral structure and the ACL in restraining simulated clinical laxity in both the intact and ACL-deficient knee. Study Design: Controlled laboratory study. Methods: A total of 16 knees were tested using a 6 degrees of freedom robot with a universal force-moment sensor. The system automatically defined the path of unloaded flexion/extension. At different flexion angles, anterior-posterior, internal-external, and internal rotational laxity in response to a simulated pivot shift were tested. Eight ACL-intact and 8 ACL-deficient knees were tested. The kinematics of the intact/deficient knee was replayed after transecting/resecting each structure of interest; therefore, the decrease in force/torque reflected the contribution of the transected/resected structure in restraining laxity. Data were analyzed using repeated-measures analyses of variance and paired t tests. Results: For anterior translation, the intact ACL was clearly the primary restraint. The iliotibial tract (ITT) resisted 31% ± 6% of the drawer force with the ACL cut at 30° of flexion; the anterolateral ligament (ALL) and anterolateral capsule resisted 4%. For internal rotation, the superficial layer of the ITT significantly restrained internal rotation at higher flexion angles: 56% ± 20% and 56% ± 16% at 90° for the ACL-intact and ACL-deficient groups, respectively. The deep layer of the ITT restrained internal rotation at lower flexion angles, with 26% ± 9% and 33% ± 12% at 30° for the ACL-intact and ACL-deficient groups, respectively. The other anterolateral structures provided no significant contribution. During the pivot-shift test, the ITT provided 72% ± 14% of the restraint at 45° for the ACL-deficient group. The ACL and other anterolateral structures made only a small contribution in restraining the pivot shift. Conclusion: The ALL and anterolateral capsule had a minor role in restraining internal rotation; the ITT was the primary restraint at 30° to 90° of flexion. Clinical Relevance: The ITT showed large contributions in restraining anterior subluxation of the lateral tibial plateau and tibial internal rotation, which constitute pathological laxity in ALRI. In cases with ALRI, an ITT injury should be suspected and kept in mind if an extra-articular procedure is performed.

Posteromedial Meniscocapsular Lesions Increase Tibiofemoral Joint Laxity With Anterior Cruciate Ligament Deficiency, and Their Repair Reduces Laxity

Background: Injury to the posteromedial meniscocapsular junction has been identified after anterior cruciate ligament (ACL) rupture; however, there is a lack of objective evidence investigating how this affects knee kinematics or whether increased laxity can be restored by repair. Such injury is often overlooked at surgery, with possible compromise to results. Hypotheses: (1) Sectioning the posteromedial meniscocapsular junction in an ACL-deficient knee will result in increased anterior tibial translation and rotation. (2) Isolated ACL reconstruction in the presence of a posteromedial meniscocapsular junction lesion will not restore intact knee laxity. (3) Repair of the posteromedial capsule at the time of ACL reconstruction will reduce tibial translation and rotation to normal. (4) These changes will be clinically detectable. Study Design: Controlled laboratory study. Methods: Nine cadaveric knees were mounted in a test rig where knee kinematics were recorded from 0° to 100° of flexion by use of an optical tracking system. Measurements were recorded with the following loads: 90-N anterior-posterior tibial forces, 5-N·m internal-external tibial rotation torques, and combined 90-N anterior force and 5-N·m external rotation torque. Manual Rolimeter readings of anterior translation were taken at 30° and 90°. The knees were tested in the following conditions: intact, ACL deficient, ACL deficient and posteromedial meniscocapsular junction sectioned, ACL deficient and posteromedial meniscocapsular junction repaired, ACL patellar tendon reconstruction with posteromedial meniscocapsular junction repair, and ACL reconstructed and capsular lesion re-created. Statistical analysis used repeated-measures analysis of variance and post hoc paired t tests with Bonferroni correction. Results: Tibial anterior translation and external rotation were both significantly increased compared with the ACL-deficient knee after posterior meniscocapsular sectioning (P < .05). These parameters were restored after ACL reconstruction and meniscocapsular lesion repair (P > .05). Conclusion: Anterior and external rotational laxities were significantly increased after sectioning of the posteromedial meniscocapsular junction in an ACL-deficient knee. These were not restored after ACL reconstruction alone but were restored with ACL reconstruction combined with posterior meniscocapsular repair. Tibial anterior translation changes were clinically detectable by use of the Rolimeter. Clinical Relevance: This study suggests that unrepaired posteromedial meniscocapsular lesions will allow abnormal meniscal and tibiofemoral laxity to persist postoperatively, predisposing the knee to meniscal and articular damage.

Effect of Medial Patellofemoral Ligament Reconstruction Method on Patellofemoral Contact Pressures and Kinematics

Background: There remains a lack of evidence regarding the optimal method when reconstructing the medial patellofemoral ligament (MPFL) and whether some graft constructs can be more forgiving to surgical errors, such as overtensioning or tunnel malpositioning, than others. Hypothesis: The null hypothesis was that there would not be a significant difference between reconstruction methods (eg, graft type and fixation) in the adverse biomechanical effects (eg, patellar maltracking or elevated articular contact pressure) resulting from surgical errors such as tunnel malpositioning or graft overtensioning. Study Design: Controlled laboratory study. Methods: Nine fresh-frozen cadaveric knees were placed on a customized testing rig, where the femur was fixed but the tibia could be moved freely from 0° to 90° of flexion. Individual quadriceps heads and the iliotibial tract were separated and loaded to 205 N of tension using a weighted pulley system. Patellofemoral contact pressures and patellar tracking were measured at 0°, 10°, 20°, 30°, 60°, and 90° of flexion using pressure-sensitive film inserted between the patella and trochlea, in conjunction with an optical tracking system. The MPFL was transected and then reconstructed in a randomized order using a (1) double-strand gracilis tendon, (2) quadriceps tendon, and (3) tensor fasciae latae allograft. Pressure maps and tracking measurements were recorded for each reconstruction method in 2 N and 10 N of tension and with the graft positioned in the anatomic, proximal, and distal femoral tunnel positions. Statistical analysis was undertaken using repeated-measures analyses of variance, Bonferroni post hoc analyses, and paired t tests. Results: Anatomically placed grafts during MPFL reconstruction tensioned to 2 N resulted in the restoration of intact medial joint contact pressures and patellar tracking for all 3 graft types investigated (P > .050). However, femoral tunnels positioned proximal or distal to the anatomic origin resulted in significant increases in the mean medial joint contact pressure, medial patellar tilt, and medial patellar translation during knee flexion or extension, respectively (P < .050), regardless of graft type, as did tensioning to 10 N. Conclusion: The importance of the surgical technique, specifically correct femoral tunnel positioning and graft tensioning, in restoring normal patellofemoral joint (PFJ) kinematics and articular cartilage contact stresses is evident, and the type of MPFL graft appeared less important. Clinical Relevance: The correct femoral tunnel position and graft tension for restoring normal PFJ kinematics and articular cartilage contact stresses appear to be more important than graft selection during MPFL reconstruction. These findings emphasize the importance of the surgical technique when undertaking this procedure.

Anterolaterale Stabilisierung@@@Anterolateral stabilization: Operationstechnik@@@Surgical technique

ZusammenfassungDie anterolaterale Rotationsinstabilität erfährt zurzeit ein zunehmendes Interesse bezüglich biomechanischer Grundlagen und chirurgischer Lösungsstrategien. Die hier vorgestellte Möglichkeit zur anterolateralen Stabilisierung orientiert sich an einer in den 1980er Jahren bereits beschriebenen Technik, wurde jedoch anhand aktueller biomechanischer Erkenntnisse unter Verwendung moderner Verankerungsprinzipien modifiziert. Sowohl in bisherigen biomechanischen Untersuchungen als auch in der täglichen Praxis bietet diese zur vorderen Kreuzbandrekonstruktion additive Methode eine einfache, effektive und reproduzierbare Möglichkeit zur anterolateralen Stabilisierung.AbstractAnterolateral rotatory instability has recently experienced growing interest regarding biomechanical principles and surgical reconstructive strategies. The presented technique for anterolateral stabilization is based on a technique first described in the 1980s and has been modified according to recent biomechanical knowledge and modern fixation principles. Following recently acquired biomechanical data and our routine experience in combination with anterior cruciate ligament (ACL) reconstruction this technique provides an easy, effective and reproducible option for anterolateral stabilization.

Partial proximal tibia fractures

Partial tibial plateau fractures may occur as a consequence of either valgus or varus trauma combined with a rotational and axial compression component. High-energy trauma may result in a more complex and multi-fragmented fracture pattern, which occurs predominantly in young people. Conversely, a low-energy mechanism may lead to a pure depression fracture in the older population with weaker bone density. Pre-operative classification of these fractures, by Müller AO, Schatzker or novel CT-based methods, helps to understand the fracture pattern and choose the surgical approach and treatment strategy in accordance with estimated bone mineral density and the individual history of each patient. Non-operative treatment may be considered for non-displaced intra-articular fractures of the lateral tibial condyle. Intra-articular joint displacement ⩾ 2 mm, open fractures or fractures of the medial condyle should be reduced and fixed operatively. Autologous, allogenic and synthetic bone substitutes can be used to fill bone defects. A variety of minimally invasive approaches, temporary osteotomies and novel techniques (e.g. arthroscopically assisted reduction or ‘jail-type’ screw osteosynthesis) offer a range of choices for the individual and are potentially less invasive treatments. Rehabilitation protocols should be carefully planned according to the degree of stability achieved by internal fixation, bone mineral density and other patient-specific factors (age, compliance, mobility). To avoid stiffness, early functional mobilisation plays a major role in rehabilitation. In the elderly, low-energy trauma and impression fractures are indicators for the further screening and treatment of osteoporosis. Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.160067. Originally published online at www.efortopenreviews.org

Return to Play Following Tendon Injuries

Quadriceps or patellar tendon ruptures are rare but severe injuries in football. Most ruptures are the result of degenerative weakness of the tendon, and accordingly the incidence in young active football players is relatively low. Complete ruptures of these tendons should be operated on by direct repair of the tendon. The healing process of the tendon can be divided into three parts (inflammatory, regenerative, and remodeling phase). The rehabilitation protocol should be adapted to these phases. In the first 6 weeks of rehabilitation, the repaired tendon should be protected via partial weight-bearing to support the inflammatory and regenerative phase. After 6 weeks, the tendon loading can be increased to support the remodeling phase with alignment of collagen fibers. During this restrictive rehabilitation, weakening of the muscles and proprioceptive system is expectable and should be compensated in the later rehab phase. Return-to-play decision should be related to healing process of the rupture and rehabilitation of the lack of muscle strength and proprioception. Therefore, a return to play (RTP) test checking these parameters should be performed. The rate of RTP after quadriceps or patellar tendon ruptures is high, but the total healing time is often between 6 and 12 months.

The posterior horn of the lateral meniscus is a reliable novel landmark for femoral tunnel placement in ACL reconstruction

PurposeFemoral tunnel placement is essential for good outcome in anterior cruciate ligament (ACL) reconstruction. In the past, several attempts have been made to optimize femoral tunnel placement. It was observed that the posterior horn of the lateral meniscus was always located directly below to the desired femoral ACL tunnel position, when the knee was brought to deep flexion (> 120°). The goal of the present study was to verify the hypothesis that the posterior horn of the lateral meniscus can be used as a landmark for femoral tunnel placement.MethodsOut of a consecutive series of ACL reconstructions done by a single surgeon, 55 lateral radiographs were evaluated according to the quadrant method by Bernard and Hertel. Additionally, on anterior-posterior radiographs the femoral tunnel angle was determined.ResultsIn the present case series the posterior horn of the lateral meniscus could be identified and used as a landmark for femoral tunnel placement in all cases. The mean tunnel depth was 24 ± 5.1% and the mean tunnel height was 31.3 ± 5.7%. The mean femoral tunnel angle was 41 ± 4.9° using the anatomical axis as a reference. Compared to previous cadaver studies the data of the present study were within their anatomical range of the native ACL insertion site.ConclusionThe suggested technique using the posterior horn of the lateral meniscus as a landmark for femoral tunnel placement showed reproducible results and matches the native ACL insertion site compared to previous cadaveric studies. In particular, non-experienced ACL surgeons will benefit from this apparent landmark and the corresponding easy-to-use ACL reconstruction method.Level of evidenceIV.

Biomechanics of the Anterolateral Structures of the Knee

This article describes the complex anatomic structures that pass across the lateral aspect of the knee, particularly the iliotibial tract and the underlying anterolateral ligament and capsule. It provides data on their strength and roles in controlling tibiofemoral joint laxity and stability. These findings are discussed in relation to surgery to repair or reconstruct the anatomic structures, or to create tenodeses with similar effect.

The influence of posterior medial meniscocapsular lesions on tibiofemoral joint laxity with ACL deficiency and reconstruction

Introduction: Injury to the posterior medial meniscocapsular junction (the ‘ramp’ lesion) occurs at the time of anterior cruciate ligament (ACL) rupture (10-24% of cases); however there is a lack of objective evidence investigating how this affects knee kinematics. It is often missed when viewed arthroscopically from the front of the medial compartment as it can only be seen with the arthroscope in the posteromedial recess. Objectives: To investigate the biomechanical impact of the ‘ramp lesion’ on the ACL deficient and ACL reconstructed knee and the impact of suture repair of the lesion on the same knee states. Methods: Nine fresh frozen cadaveric knees were mounted in a 6 degrees of freedom rig where knee kinematics were recorded at 10° intervals from 0°-100° using an optical tracking system. Measurements were recorded using the following loading conditions: 90 N anterior and posterior tibial forces, 5 Nm internal and external tibial rotation torques, and a combined 90 N anterior tibial force and 5 Nm external tibial rotation torque. Manual Rolimeter readings of anterior translation were taken at 30° and 90°. The knees were tested in the following order: (1) intact, (2) ACL deficient, (3) ACL deficient + posterior meniscocapsule sectioned, (4) ACL deficient + posterior meniscocapsule repaired, (5) ACL patellar tendon reconstruction with posterior meniscocapsule repair and (6) ACL reconstructed + capsular lesion re-created. Statistical analysis was undertaken using repeated-measures ANOVA and post-hoc paired t-tests with Bonferonni correction. Results: Tibial anterior translation and external rotational laxities were both significantly increased compared to the ACL deficient knee following posterior meniscocapsular sectioning (P < 0.05). These were both restored following ACL reconstruction and meniscocapsular lesion repair (P > 0.05). Significant changes in anterior tibial translation between the different knee states were identified with the Rolimeter, indicating these changes are clinically detectable (P < 0.05). Conclusion: Anterior and external rotational laxities were significantly increased after mimicking the ‘ramp lesion’ by sectioning of the posteromedial meniscocapsular junction in an ACL-deficient knee. These were not restored after ACL reconstruction alone but were restored with ACL reconstruction combined with posterior meniscocapsular repair. Tibial anterior translation changes were clinically detectable by use of the Rolimeter. This study suggests that unrepaired posteromedial meniscocapsular lesions will allow abnormal meniscal and tibiofemoral laxity to persist postoperatively, predisposing the knee to meniscal and articular damage but also adding avoidable extra strain on an ACL graft, which may yield.

Scientific Basis and Surgical Technique for Iliotibial Band Tenodesis Combined with ACL Reconstruction

Anatomy: Due to the complexity of the lateral side of the knee, it may be best to describe these structures in terms of three tissue layers from superficial to deep. The distal part of the fascia lata – (1) the superficial layer of the iliotibial band (ITB) – is tethered to the distal femur by the (2) deep and capsulo-osseous fibres of the ITB. Removal of these ITB layers exposes the (3) anterolateral capsule and other deeper structures, which has been described as including the anterolateral ligament (ALL) with differing interpretations.